Internal combustion engines are designed to operate in a designated range of temperatures. When engine temperature becomes excessive, even for relatively short durations, engine performance is diminished and at extreme temperatures severe engine damage can result. Such damage can include burned valves, head gasket failures, engine block distortion, cracked manifold and cylinder heads, burning and scoring of pistons, carbon deposits behind piston rings and on injector tips, piston ring failures with resultant high oil consumption and blow by, lubrication oil dilution, cracks in the turbocharger unit and expansion of aluminum pistons resulting in aluminum deposits on the cylinder walls and piston seizure.
A common cause of excessive engine temperatures is air filter clogging. As the air filter becomes clogged, the available inlet air is decreased and the air/fuel ratio can become too rich, thereby causing the engine temperature to increase. If the operator neglects to change a clogged filter, the engine temperature can reach levels sufficient to cause the above-mentioned damage.
The present invention is directed to overcoming one or more of the problems set forth above by providing a system which detects filter clogging and reduces the available engine power. The present invention has at least two advantages over known systems. First, by limiting engine power when the filter is clogged, the engine temperature can be maintained at levels below those where damage results. Second, the system "encourages" the operator to replace a clogged filter by preventing full power operation of the vehicle as the filter clogging increases.